Experienced physiotherapy practitioners are realising that the use of nutritional supplementation emphasises an holistic approach to the treatment of musculoskeletal injuries which results in quicker recovery, enhanced sporting performance as well the prevention of further injury, through better recovery.
Nutritional goals in athletes have several of the following elements.
- They are not static and vary depending upon calorific need and weight requirements. Periodization of training and nutritional needs should complement one another
- Nutritional plans need to be presonalised to the specific sport, specific position (task), practicalities, preferences as well as varied depending upon the response to nutritional interventions
- Competition nutritional strategies focus on providing adequate fuel to meet the demands of the event as well as support cognitive function.
- Assessment of energy cost of exercise vs energy availability
- Achievement of body composition in line with health as well as sporting requirments
- Timing of nutrition to various parts of the day rather than 'per day' and should be calculated by individual body mass.
- Pragmatic approach to the use of supplements and 'sports foods'.
Relative energy deficiency in sport (RED-S) includes considerations of optimal body function once the energy requirements of the sport have been removed. Specifically, health consequences including menstrual function, bone health, endocrine, metabolic, hematologocal, growth and development, psychological, cardiovascular, gastrointestinal and immunological systems.
Ketogenic diets and Exercise
Ketogenic diets have become popular in the decade of the teens. It involves fasting up to 16 - 18 hours between meals (Dinner at 7 and lunch the following day at 1pm) as well as maintaining a strict low carbohydrate diet. In principle, this methodology, similar to repeated acute bouts of exercise, presumably encourages the fat mobilising/oxidative pathways whilst sparing glucose. Although, investigations into liver metabolic pathways to ketogenic diet and exercise, in mice, have shown them not to be additive, they have found both enhanced liver enzymes and pancreatic enzymes used to metabolise fat (Huang et al 2020, Med Sc Sp Ex, 52,1 37-48). Anecdotal evidence suggest that this glycogen sparing diet can be beneficial even in ultra-endurance type of events.
When working at high intensities, carbohydrates provide the most efficient source of fuel for ATP per volume of oxygen, in the mitochondria. The size of carbohydrate stores are limited, however they can be acutely manipulated, expecially in prolongied sustained or high intensity exercise, maintenance of carbohydrate availability enhances performance. Carbohydrate plays direct and indirect roles in the muscles adaptation to training. An example of the latter is the commencement of a second bout of training before the restoration of carbohydrate stores results in a co-ordinated up-regulation of the transcriptional and post transcriptionsl responses to exercise. Additionally, carbohydrate restriction during exercise can alter and improve mitochondrial oxidation of lipids. Periodization of training and of carbohydrate loading and unloading are techniques used to manipulate athletes performance.
Short term restriction of carbohydrate (CHO), when using a ketogenic diet, were shown to effect iron deficiences via the modulation of interleukin-6 (IL-6) and hepcidin levels. Acutely, the iron levels of a ketogenic diet were lower than in the CHO rich group. This may be partly due to the removal of the large iron content in the western CHO rich diet, but also as a result of a positive change to functional iron use such as increased erythropoiesis, DNA synthesis, and oxidative enzyme production. After a 3 week adaption of elite walkers to a ketogenic diet, the CHO rich diet group showed a greater decrement to serum ferritin despite greater IL-6 and hepcidin responses in the ketogenic diet group (McKay et al Med Sc Sp Ex, 51, 3, 548-555). Such a paradoxical response suggests the need to periodically check ferritin levels.
Patency of blood vessels may be critical to good joint health. Elevated cholesterol levels are thought to affect blood vessel patency, as the formation of plaques within the vessels results in the relationship of blood particle number (Reynolds Number) and blood flow becoming critical causing stasis and end vessel infarction. The articular joints tend to be at the end of the line for blood vessels and hence their small diameter may be critically compromised by elevated cholesterol levels. Hence, supplementation with anti-cholesterol agents such as 1000mg of EPA and DHA in Fish Oil, the use of Co-enzyme Q10 may go some way to mitigating the effects of cholesterol.The incidence of people, who are on cholesterol inhibiting statins, suffering from myalgia has been reported to be between 1 and 25%. There appears to be a link with mitochondrial Co-enzyme Q10 deficiency. There have been mixed reports on the effect of CoEnzymeQ10 supplementation on myalgia (Parker & Thompson 2012, Ex&SpScReviews, 40, 4, 188-194). However, in the abscence of any contra-indications to using CoEnzymeQ10 supplementation it would to be wise to use it, if participating in physical activity where post exercise muscle soreness is a common complaint.
Glucosamine (1200mg) and chondroitin sulphate (800mg) combine with methylsulfonylmethane (MSM) (800mg) are considered important in improving the production and/or size of hyaluronic acids as well as regulating the expression of matrix-degrading enzymes and their inhibitors. Furthermore, the concentration of sulphur in arthritic cartilage has been shown to drop to 1/3, thereby suggesting a role for MSM supplementation. High quality fish oils with an EPA and DHA concentrations of at least 1000mg is thought to have an inhibitory effect on arachidonic acid metabolism (Petra Hunt 2012, FX Medicine, 66, 10-11). Furthermore, fish oils anti-oxidating effect and it's balancing effect on hyperlipidemia suggests that it may have a role to play in tendon degeneration where immune-metabolic compromise has been found to be an important aspect of tendon degeneration and necrosis (see shoulder section elsewhere on this site). CoQ10 is also thought to help in the reduction of cholesterol and the enhancement of mitochondrial oxidative activity which, presumably, would also be good for tendons. Fish oils have also been associated with cognitive functioning, whose compromise can lead to irritability, depression and reduced immune function.
Compromised intestinal barrier function in people with food intolerances has been associated with inflammation at extraintestinal sites, including the joints. Evidence supports the relationship between the gastrointestinal microbiota, the mucosal and systemic immune responses and the development of arthritis. In fact, glucosamine has been shown, by A/Prof Luis Vitetta (Uni Qld), to have more favorable effects in patients with larger amounts of favorable enteric bacteria. Hence, some new therapies include the use of pro-biotics in the treatment of joint disease.
Pernicious anemia is an auto-immune disease that affects the gastric mucosa specifically affecting the absorption of Vit B12. In Helycobacter pylori Vit B12 absorption is also compromised. Vit B12 activates folate and is essential for nervous system function. People suffering from type II diabetes and using Metformin have also been seen to have reduced Vit B12 status (Reynolds 2012, FX Medicine, 66, 18-19). Additionally, impaired iron status is a prevalent problem among female endurance athletes and may affect performance due to reduced haemoglobin oxygen carrying capacity (Dellavalle & Haas 2012, Med Sc Sp Ex, 44, 8, 1552-1559)
Creatine supplementation appears to have beneficial affects in knee osteoarthritis in post menopausal women. These benefits included increased physical function, lower limb lean mass, and improved quality of life (Neves et al 2011 Med Sc Ex Sp, 43, 8, 15381543).
Treatment of fibromyalgia has included the use of supplements such as Vitamin D, magnesium, malic acid and acetyl-L-Carnitine (Leng 2012, FX Medicine, 66, 16-17). Malic acid has also been implicated in the reduction of cholesterol through it's mobilising affect on Billirubin, which emulfasises fat. Malic acid is found in the apple peel. Curcumin, Green Tea, Devils Claw and Cats Claw have been used to improve natural system anti-inflammatory and anti-oxidant responses. They have also been used for the treatment of Alzheimers.
Montmorency Cherry Juice reduces muscle damage caused by intensive strength training exercise (Bowtell et al 2011, Med Sc Sp Ex, 43, 8, 1544-1551). It is thought that the improvements in isometric muscle strength after intensive training were as a result of the anti-oxidant and anit-inflammatory properties of polyphenolic compounds including flavanoids and anthocyanins.
If resistance training is performed at low intensities and where blood flow is occluded similar results are obtained as with high intensity resistance training. These muscle anabolic protein synthesising effects are even more pronounced with the supplementation of essential amino acids (EAA's) after training, particularly in the aging population. This is likely to be mediated through mTORC1 signaling in human skeletal muscle (Walker et al 2011, Med Sc Ex Sp, 43, 12, 2249-2258).
Blood flow may be improved with the consumption of Beetroot Juice. Beetroot juice has been found to be full of nitrate, which when consumed is converted to nitrous oxide in the mouth. Nitrous oxide not only has been shown to reduce pain but it also acts as a vasodilator, opening blood vessels, allowing more blood and oxygen to be delivered to muscles. Additionally, nitrate may also reduce the energy cost of exercise and improve muscle contractions. Fortunately, it is easy to juice up a beetroot in the blender.
Energy requirements of endurance events
Cramping and delayed onset muscle soreness (DOMS) are frequent complaints of novice and elite endurance athletes. Specific eccentric exercise training has been shown to change the glycolytic capacity of muscles to a more potent oxidative state (Hody et al 2011, Med Sc Ex Sp, 43, 12 2281-2296). Hence a direct mechanical input results in a change of metabolism. Therefore, it is plausible that enhancing metabolism during training through nutritional considerations would have a far more reaching effect than training alone.
Carbohydrate recommendations for athletes range from 6 to 10 g.kg body weight per day and can range from 50-70% of total calories.
Protein recommendations for endurance and strength-trained athletes range from 1.2 to 1.7 g.kg body weight per day and can range from 10% to 35% of total calories. Protein recommendations can typically be met through diet alone.
Fat intake should range from 20% to 35% of total energy intake. Rule of 3's, 1/3 saturated fat, 1/3 polyunsaturated fats, 1/3 monosaturated fats
Micronutrients are essential for athletic activity and should be consummed at the recommended dietary allowances. Important micronutrients include calcium, vitamin D, B vitamins, iron, zinc, magnesium, and antioxidants such as vitamins C and E, beta carotene, and selenium.
Fluids are required to maintain adequate hydration and regulate body temperature (thermoregulation) and may be a source of energy (in forms of calories).
An example of energy requirements in Professional cycling
- 80-120 race days
- 27,000 - 39,000km/yr
- Tour de France 3 week race can be lost by 3 minutes, a fraction of the overall time
- In the pelliton they consume on average 200W @ 40km/hr and uphill approx 400w
- 26 cheese burgers is the calorific equivelent for 1 days racing (approx 9000Kcal)
- Sweat rate approx 1 litre/hr
- Average fluid loss 2.1litres +/- 0.6litres (in cooler months)
- Occasionally in the Tour de France fulid loss is of the magnitude of 4litres
- Percentage body fat of profesional cyclists is 3-6%
- Flat terraine Oxygen consumption of 5.5 -> 7 l.min
- In the pelliton there is a decrease of 40% of oxygen consumption
- Dehydration can reduce strike volume by 28% thereby significantly reducing cardiac output as the 13% increase in heart rate isn't enough to compensate. The reduction in blood pressure also leads to reduced muscle perfusion
- 1g of carbohydrate combines with 1g water, therefore adquate fluid consumption is required for carbohydrate loading
- Pre exercise carbohydrate loading combined with carbohydrate-protein supplementation immediately and up to 4 hours after exercise may reduce the release of stress hormones and hereby reduce immune function compromise
- Anti-oxidants should reduce post exercise inflammatory response by 'mopping up' oxygen free radicals
- There appears to be an increased incidence of retro-lymphatic malignancies in endurance athletes
- If doing repeated bouts of exercise, a 3 to 6 hour recovery may be enough time to re-establish post-immune depression to acceptable levels
- Adipose tissue triglycerides can provide 50 000 - 100 000 Kcals, whereas the liver glycogen can only provide energy of 200 - 400 Kcals
Other examples from sport include a detailed analysis of the requirements of each team player in that sport. For example in Australian Rules Football, a mid field player runs between 17 and 23km per game, whereas the goal kickers and defenders run much less, which means that their energy requirements are substantially different.
Cellular Immune Response to Muscle Trauma
Exercise is considered benefical to immune health. However, the cellular response to trauma from exercise requires good post exercise recovery, using rest and nutritional supplementation.
Generally, supplementation during and immediately after exercise is critical to immune well being. German researchers found that non alcoholic beer reduces inflammation and incidence of respiratory tract illness (Scherr et al, 2012, Med Sc Sp Ex, 44, 1, 18-26). Furthermore, other investigators have demonstrated that protein ingested immediately before sleep is effectively digested and absorbed, thereby stimulating muscle protein synthesis and improving whole-body protein balance during post exercise overnight recovery (Res et al 2012. Med Sc Sp Ex, 44, 8, 1560 -1569). This is important as negative nitrogen balance has been implicated in post exercise immune compromise (Krause 2005). Please see elsewhere on this site for further explanations on the immune system.
Caffeine consumption may improve contractile activity, improve concentration as well as aid the mobilisation of free fatty acids required for the Beta Hydroxylase pathway. Caffeine has been shown to improve total time, decision time and movement time as well as enhance reactive agility after a simulated team-sport exercise (Duvnjak-Zaknich et al 2011 Med Sc Sp Ex, 43, 8, 1523-1530). However, excessive consumption of caffeine may cause anxiety and dehydration.
Constituents of carbohydrate gel supplements (per serving) commonly used in Australia
- CHO choice shouldn't impede stomach emptying thus interfering with fluid delivery
- CHO shouldnt cause G.I. problems
- Ideally drinks should contain 4-8 % CHO
- If hunger is a problem, try using real foods such as bananas and breakfast bars instead of supplements such as sports gels
- Variety of foods (both sweet and savoury) important to prevent 'flavour fatigue'
During the 2006 Tour de France, athletes used power output (P=Ft) to determine the pace of their race. Similarly, they calculated energy expenditure (W=Pt) to determine the amount of calories (up to 6000 Kcals) they needed to replace each day. Hereby, the 'tank' shouldn't run dry, nor power output dwindle.
1st Law of thermodynamics : energy in = energy out
If you can estimate the % Vo2 that an athlete is working at, and if you know for what period of time they are working at this rate, then you can calculate an estimate of energy need during their event
- Ultra-endurance events > 4 hours, normal glycogen stores are inadequate to maintain exercise
- Depletion of CHO stores is a major cause of fatigue during endurance exercise
- CHO loading pre-event may increase glycogen stores by 200%
| || |
Cramping and DOMS
Causes of cramping are multifactorial and theories have included an ion imbalance of magnesium and potassium, lack of energy, reduced blood flow, poor diet, and inadequate training when preparing for an event.
Endurance athlete investigations using magnesium as the 'variable' in cramping is based on the fact that magnesium acts as a 'gate keeper' to calcium i.e. controlling the flow of calcium across the sarcolemma, to the intracellular space (sarcoplasm), as well as acting on neurones in the central nervous system. Since magnesium acts as a regulator to calcium it may prevent leakage of calcium into the sarcoplasmic reticulum as well as aiding the muscles relaxation phase after each and every nerve impulse. At a central nervous system level, it acts in the wide dynamic range neurons which are responsible for the modulation of pain impulses. Magnesium is also thought to improve insulin sensitivity. The recommended dose of magnesium orotate is 300mg per day.
Sodium and potassium on the other hand reside in the muscle membrane and are involved in the ionic depolorisation of the membrane, which then leads to the release of calcium from the sarcoplasmic reticulum. The quinine in tonic water may aid in the stabilisation of this membrane, however electrolytes still need to be present. With water intoxication the thought is that the sodium concentration has been diluted down from too much water. Researchers have recommended to 'drink to thirst' in order to avoid 'water intoxication' (Hoffman & Stuempfle 2016, Med Sc Ex Sp, 47, 9, 1781-1787)
Vitamin D supplementation : There are several novel key implications for practice that arise from research by Owens et al (2017), Medicine & Science in Sports & Exercise . 49(2):349-356, February 2017. First, they speculate that high-dose bolus supplementation with vitamin D3 is likely to be detrimental to the intended targeted downstream biological functions because of significant increases in the negative regulatory molecule 24,25[OH]2D. Weekly doses amounting to more than 5000 IU·d−1 may need to be reassessed in light of our data. Rapid withdrawal from high-dose supplementation may result in adverse outcomes as the concentration of 24,25[OH]2D3 remains elevated for several weeks after withdrawal from supplementation despite declines in 1,25[OH]2D3. If moderate to high doses of vitamin D3 have been administered, a gradual withdrawal from supplementation is advisable. At present, the optimal approach has not been established. Lower doses administered often (daily) may offer the most potent beneficial biological effects and limit the transactivation of CYP24A1 and the subsequent production of the negative regulatory molecule 24,25[OH]2D3.
Another mechanism of cramping may be the lack of ATP - the energy substrate required for the release of the contraction between the myofilaments (see end of endurance_training). The natural state for a muscle is contraction e.g. 'rigor mortice', and energy releases the contraction to allow shortening and lengthening of the muscle. Inadequate release of the muscle during the eccentric (muscle lengthening) phase of contraction can lead to broadening and streaming of the 'Z-bands' and thereby the loss of muscle structural integrity. This is thought to lead to DOMS, which can take a muscle up to 28 days to recover from. Additionally, the aforementioned Sodium-Potassium ionic membrane channels require energy in the form of ATP. Carbohydrate loading prior to an event is also a commonly used strategy to prevent fatigue and thus cramping.
Lactic acid has been traditionally blamed for the loss of performance. However, lactate is used by endurance athletes to produce pyruvate in the liver, thus supplying the system with energy. There is even data to suggest that lactic acid is produced and used at rest for energy supplies. Dr Toni Held demonstrated that over 50% of elite orienteers cognitive abilities in map, object and spatial recognition improved when exercising above anaerobic threshold. This is unfortunately unpublished data as the conventional 'wisdom' and 'group think' at the time (1986) didn't feel that this was conceivable!!! Therefore, lactate may not be as bad as people suggest and I personally remember thriving on lactate when I was really fit and competing at orienteering in Europe.
Importantly, these reactions require adequate blood flow for the transportation of energy to the sites of contraction as well as removal of metabolic byproducts from the contractions. This adequacy includes the maintenance of the blood volume which can be lost through sweat. Additionally, cardiac output is a product of heart rate x stroke volume. Therefore, if the volume of blood reduces, cardiac output must be compensated by rises in heart rate and/or changes in blood pressure. The latter being a strong contra-indication to further exercise. It must be remembered that heat exhaustion can be fatal! However, sweating alone is not the cause of cramping, since even concert musicians can cramp in the absence of profuse sweating.
Blood vessel patency
There is evidence to suggest maintaining blood vessel patency in the form LDL cleansers such as omega-3 and omega-6 free fatty acids may be of value for optimising performance. Since the metabolic reactions in the muscles produce a high oxygen free radical loading, the use of Vitamin E as an anti-oxidant has also been advocated. However, a recent publication suggested potential increased risk of heart disease if taking Vit E for prolonged periods (in this case 7 years). People have suggested that the high berry and raw fish (Herrings) diet of the Scandinavians and the root and Sushi diet of the Japanese has contributed to their longevity due to the high anti-oxidant content and cleansing nature of these foods. However, it must also be remembered that these people live in cold climates and their culture propagates participation in regular exercise (e.g. riding the bicycle to work, school and shopping). Interestingly, Scandinavian populations in North America don't seem to maintain their longevity to the same extent, possibly due to the highly processed nature of those foods and lack of exercise.
Recently, the use of a combination of carbohydrate and protein supplements before, during and after exercise have been advocated. The theory being that protein can be highly restorative to muscle tissue. I personally use the Endura products for Creatine, HMB, Magnesium and Carbohydrate-protein supplementation. Quercetin has been shown to improve endurance capacity (Kresseler et al 2011, Med Sc Sp Ex, 43, 12, 2396-2404). Quercetin is a polyphenolic flavonoid found in several plant foods, including the skins of grapes, onions, and apples. It has been implicated as cardioprotective, anticarcinogenic, antioxidant, antiapoptotic and ergogenic.
Hence, the causes of cramping are multi-factorial. Generally, cramping occurs when muscles are asked to contract beyond their normal nature of exercise. Therefore, diet supplementation is not a substitute for adequate training. Never-the-less fluid, electrolyte and most importantly energy replacement during a long distance event is essential in the maintenance of performance and prevention of DOMS. Athletes should consult a sports dietician for specific advice.
Exercise and Glycemic Imbalances: A Situation-Specific Estimate of Glucose Supplement
FRANCESCATO, MARIA PIA; GEAT, MARIO; ACCARDO, AGOSTINO; BLOKAR, MARCO; CATTIN, LUIGI; NOACCO, CLAUDIO
Medicine & Science in Sports & Exercise. 43(1):2-11, January 2011.
Purpose: The purposes of this study were to describe a newly developed algorithm that estimates the glucose supplement on a patient- and situation-specific basis and to test whether these amounts would be appropriate for maintaining blood glucose levels within the recommended range in exercising type 1 diabetic patients.
Methods: The algorithm first estimates the overall amount of glucose oxidized during exercise on the basis of the patient's physical fitness, exercise intensity, and duration. The amount of supplemental CHO to be consumed before or during the effort represents a fraction of the burned quantity depending on the patient's usual therapy and insulin sensitivity and on the time of day the exercise is performed. The algorithm was tested in 27 patients by comparing the estimated amounts of supplemental CHO with the actual amounts required to complete 1-h constant-intensity walks. Each patient performed three trials, each of which started at different time intervals after insulin injection (81 walks were performed overall). Glycemia was tested every 15 min.
Results: In 70.4% of the walks, independent of the time of day, the amount of CHO estimated by the algorithm would be adequate to allow the patients to complete the exercise with a glucose level within the selected thresholds (i.e., 3.9-10 mmol·L-1).
Conclusions: The algorithm provided a satisfactory estimate of the CHO needed to complete the exercises. Although the performance of the algorithm still requires testing for different exercise intensities, durations, and modalities, the results indicate its potential usefulness as a tool for preventing immediate exercise-induced glycemic imbalances (i.e., during exercise) in type 1 diabetic patients, in particular for spontaneous physical activities not planned in advance, thus allowing all insulin-dependent patients to safely enjoy the benefits of exercise.
also view Exercise and Type 2 Diabetes elsewhere on this website
Exercise and Type 1 diabetes
People with type 1 diabetes are encouraged to exercise to improve lipid profile, reduce blood pressure and enhance overall sense of well-being. However, hypoglycemia is a risk with increasing levels of physical activity. Carbohydrate beverage supplementation (8mg CHO/kg body weight/min of exercise) prior to exercise demonstrated a reduced reduction in blood glucose, whereas protein supplementation (8mg PROT/kg body weight/min of exercise) also demonstrated blood glucose sparing effects during and after exercise which was almost as much as CHO supplementation. (Dube et al, 2012, Med Sc Sp Ex, 44, 8, 1427-1432)
as a physiotherapist I suggest that athletes consult a sports dietician for more specific advice.
Last update : 18 February 2020